Effects of benzalkonium chloride and cyclosporine applied topically to rabbit conjunctiva: a histomorphometric study / Efeitos do uso tópico do conservante cloreto de benzalcônio e ciclosporina na conjuntiva de coelhos: estudo histomorfométrico

ABSTRACT Purpose: Chronic instillation of benzalkonium chloride, a preservative, has inflammatory effects on the ocular surface. However, addition of the anti-inflammatory agent cyclosporine to a therapeutic protocol may mitigate these effects. This study compared the toxic effects of a 0.1% benzalkonium chloride solution and the possible protective effect of 0.05% cyclosporine when applied topically to the rabbit conjunctiva. Methods: Fifteen age- and weight-matched, female New Zealand white rabbits were categorized into three groups and treated for 30 consecutive days. Group 1, 2, and 3 - benzalkonium chloride received 0.1% every 24 h, 0.05% cyclosporine every 6 h, and both treatments, respectively. In each rabbit, the left eye was subjected to treatment and the right eye was a control. The rabbits were euthanized at after the experiment. Goblet cells and blood vessels were then enumerated in conjunctival tissues stained with periodic acid-Schiff and hematoxylin-eosin, respectively. Differences between treated and untreated eyes and between groups were compared using the t-test and analysis of variance. Results: Benzalkonium chloride treatment, with and without cyclosporine, significantly reduced (p≤0.05) in the number of goblet cells in treatment eyes compared with that in respective control eyes. Alternatively, adding cyclosporine to benzalkonium chloride did not prevent the loss of conjunctival goblet cells, and a significant reduction in the number of goblet cells was noted. Benzalkonium chloride-induced significant increase in the number of new blood vessels was mitigated significantly by the addition of cyclosporine. Conclusion: This study demonstrated the magnitude of conjunctival injury caused by chronic instillation of benzalkonium chloride. Although cyclosporine did not mitigate the effects on goblet cells, its addition minimized inflammatory angiogenesis induced by benzalkonium chloride.

RESUMO Objetivo: A instilação crônica de cloreto de benzal­cônio, um conservante, tem efeitos inflamatórios na superfície ocular. No entanto, a adição do agente anti-inflamatório ciclosporina a um protocolo terapêutico pode atenuar esses efeitos. Este estudo comparou os efeitos tóxicos de uma solução de cloreto de benzalcônio a 0,1% e o possível efeito protetor de ciclosporina a 0,05% quando aplicado topicamente à conjuntiva de coelho. Métodos: Quinze coelhos fêmeas brancos da raça Nova Zelândia, pareados por idade e peso, foram categorizados em três grupos e tratados por 30 dias consecutivos. Os grupos 1, 2 e 3 - receberam cloreto de benzalcônio 0,1% a cada 24h, ciclosporina a 0,005% a cada 6h e ambos os tratamentos, respectivamente. Em cada coelho, o olho esquerdo foi submetido a tratamento e o olho direito foi controle. Os coelhos foram submetidos à eutanásia após o experimento. Células caliciformes e vasos sanguíneos foram então enumerados em tecidos conjuntivais corados com ácido periódico-Schiff e hematoxilina-eosina, respectivamente. As diferenças entre os olhos tratados e não tratados e entre os grupos foram comparadas usando o teste t e análise de variância. Resultados: O tratamento com cloreto de benzalcônio, com e sem ciclosporina, reduziu significativamente (p£0,05) o número de células caliciformes nos olhos tratados em comparação com os olhos controle correspondentes. Alternativamente, a adição de ciclosporina ao cloreto de benzalcônio não impediu a perda de células caliciformes conjuntivais, e foi observada uma redução significativa no número de células caliciformes. O aumento significativo induzido pelo cloreto de benzalcônio no número de novos vasos sanguíneos foi significativamente mitigado pela adição da ciclosporina. Conclusão: Este estudo demonstrou a magnitude da lesão conjuntival resultante da instilação crônica de cloreto de benzalcônio. Embora a ciclosporina não tenha atenuado os efeitos nas células caliciformes, sua adição minimizou a angiogênese inflamatória induzida pelo cloreto de benzalcônio.

Ophthalmic adverse effects of nasal decongestants on an experimental rat model / Efeitos oftálmicos adversos de descongestionantes nasais em modelo experimental com ratos

ABSTRACT Purpose: To investigate the potential effects of chronic exposure to a nasal decongestant and its excipients on ocular tissues using an experimental rat model. Methods: Sixty adult male Wistar rats were randomized into six groups. The first two groups were control (serum physiologic) and Otrivine® groups. The remaining four groups received the Otrivine excipients xylometazoline, benzalkonium chloride, sorbitol, and ethylene diamine tetra acetic acid. Medications were applied into both nostrils twice a day for 8 weeks. Before the rats were sacrificed, epithelial staining, the Schirmer test, and intraocular pressure measurements were performed under ketamine/xylasine anesthesia (50 and 5 mg/kg, respectively). Results: Epithelial defects and dry eye were common findings in all study groups. Cataracts developed in two cases clinically. Histopathological evaluation revealed many different pathological alterations in all parts of the ocular tissues such as corneal edema, polypoid proliferation and hyalinization of the vessel wall, cystic formation of the lens, retinal nerve fiber layer degeneration, and corpora amylacea formation of the lacrimal gland. Conclusions: Prolonged usage of the nasal decongestant xylometazoline and its excipients may cause ophthalmic problems such as dry eyes, corneal edema, cataracts, retinal nerve fiber layer, and vascular damage in rats. Although these results were obtained from experimental animals, ophthalmologists should keep in mind the potential ophthalmic adverse effects of this medicine and/or its excipients and exercise caution with drugs containing xylometazoline, ethylene diamine tetra acetic acid, benzalkonium chloride and sorbitol for patients with underlying ocular problems.

RESUMO Objetivo: Investigar os possíveis efeitos da exposição crônica de descongestionante nasal e seus excipientes em tecidos oculares, utilizando um modelo experimental com ratos. Métodos: Sessenta ratos Wistar adultos machos foram divididos aleatoriamente em seis grupos. Os primeiros dois grupos foram controle (soro fisiológico) e Otrivina®. Os quatro grupos restantes receberam os excipientes de Otrivina, tais como Xilometazolina, Benzalcônio, Sorbitol e Ácido Etilenodiamino Tetracético (EDTA). Os medicamentos foram aplicados em ambas as narinas dos ratos, duas vezes ao dia, durante 8 semanas. Antes que os ratos fossem sacrificados, a coloração epitelial, o teste de Schirmer e a medida da pressão intraocular foram realizados sob anestesia com Ketamina/Xilasina (50 e 5 mg/kg, respectivamente). Resultados: Defeitos epiteliais e olho seco foram achados comuns nos grupos de estudo. A catarata desenvolveu-se clinicamente em dois casos. A avaliação histopatológica revelou a existência de alterações em todas as partes dos tecidos oculares, tais como edema de córnea, proliferação polipoide e hialinização da parede vascular, formação cística da lente, degeneração da camada de fibra nervosa da retina (RNFL) e formação de corpos amiláceos da glândula lacrimal. Conclusões: O uso prolongado do descongestionante nasal Xilometazolina e seus excipientes pode causar vários problemas oftalmológicos, como olho seco, edema de córnea, catarata, RNFL e dano vascular em ratos. Embora esses resultados tenham sido obtidos a partir de animais experimentais, os oftalmologistas devem ter em mente os potenciais efeitos oftalmológicos adversos desse medicamento e/ou de seus excipientes.

Histological and immunohistochemical study of the effect of travoprost with and without benzalkonium chloride on the corneae epithelium of adult male albino rat

Chronic topical glaucoma therapy has been reported to cause deleterious changes to the ocular surface layers. Benzalkonium chloride [BAK] is the most commonly used ocular preservative, especially in antiglaucoma drugs. It is largely responsible for the ocular toxicities and inflammation associated with the chronic use of many ophthalmic solutions. This work aimed to compare structural changes in corneae epithelium of rats after chronic exposure to travoprost 0.004% eye drops preserved without BAK, travoprost 0.004% eye drops preserved with BAK and BAK alone. Forty adult male albino rats were divided into five equal groups and created topically once daily for eight weeks; group I [control group], group II received sofzia preservative system, group III received travoprost 0.004% eye drops preserved with sofzia [Travatan Z], group IV received BAK 0.015% and group V received travoprost 0.004% eye drops preserved with 0.015% BAK [Travatan]. At the end of the experiment, cortical specimens were processed for histological study by light and electron microscopes as well as immunohistochemical study with monoclonal antibody to cytokeratin-3 [CK-3]. Corneal epithelium of animals treated with BAK alone and those treated with travoprost preserved with BAK showed desquamation of epithelial cells, significant decrease of epithelial thickness, focal disruption of Bowman's membrane, loss of microvilli, cytoplasmic-vacuolation, nuclear fragmentation and swollen mitochondria with widening of intercellular spaces. lmmunohistochemical study revealed significant decrease in the expression of CK-3 in the cytoplasm of epithelial cells. However, no obious histological changes were recorded in corneal specimens in animals treated with travoptost preserved with sofzia with normal expression of CK-3 in the cytoplasm of epithelial cells. Once-daily dosing of travoprost preserved with BAR produced significant corneal epithelial changes. However, the use of glaucoma medications with alternative preservatives as sofzia can preserve corneal health

Cloreto de benzalcônio como medicação tópica / Benzalkonium chloride as topical medication

Fontes dos dados: Revisão bibliográfica obtida pela busca nas bases de dados Cochrane, MEDLINE, BIREME, LILACS e SciELO nos últimos 20 anos, utilizando-se os termos: compostos de benzalcônio, mucosa nasal, toxicidade de drogas e rinite. Síntese dos dados: O cloreto de benzalcônio é um composto amônio quaternário que possui ação umectante e detergente, com propriedades emulsificadora e germicida. Os efeitos adversos sobre o organismo têm sido estudados há mais de duas décadas. Ratos tratados com cloreto de benzalcônio por mais de quatro semanas desenvolveram, a partir do sexto dia, hiperemia da região nasal e respiração ruidosa. Em biópsias de tecido nasal de indivíduos saudáveis submetidos ao cloreto de benzalcônio, verificou-se ação deletéria sobre os cílios da mucosa nasal. Outras alterações também foram observadas, como perda da continuidade celular nas amostras de epitélio nasal, defeitos na membrana nuclear, acúmulo de grânulos e perda de organelas. Conclusões: Diferentes efeitos deletérios do cloreto de benzalcônio sobre a mucosa nasal foram demonstrados in vivo e in vitro...

Data sources: Literature review obtained by Cochrane, MEDLINE, BIREME, LILACS and SciELO databases over the last 20 years, using the terms: benzalkonium chloride compounds, nasal mucosa, drug toxicity, and rhinitis. Data synthesis: Benzalkonium chloride is a quaternary ammonium compound that has humectant and detergent actions, and emulsification and germicide properties. The adverse effects on the body have been studied for more than two decades. Mice treated with benzalkonium chloride by more than four weeks, from the sixth day, showed nasal hyperemia and a noisy breathing. In nasal tissue biopsies of healthy individuals treated with benzalkonium chloride a deleterious action on the nasal mucosa cilia was demonstrated. Also, other alterations have been observed: cell loss of continuity in nasal epithelium, nuclear membrane defects, granule accumulation and organelles loss. Conclusions: Different deleterious effects of benzalkonium chloride on the nasal mucosa have been demonstrated in vivo and in vitro. The toxicity was observed even in concentrations below found in commercial preparations and in use for short period of time. Benzalkonium chloride can cause morphological changes in mucous cilia transport; and in immune function possibly clinical implications that may bring injury in the patients...

Conjunctival changes induced by prostaglandin analogues and timolol maleate: a histomorphometric study

PURPOSE: To compare histological changes induced by antiglaucoma medications in the rabbit conjunctiva. METHODS: Fifty New Zealand rabbits were divided in 5 groups of 10 animals. The left eyes were treated daily with one drop of bimatoprost 0.03 percent, travoprost 0.004 percent, latanoprost 0.005 percent, timolol maleate 0.5 percent or artificial tears containing benzalkonium chloride (BAK) for 30 days. The right eyes served as controls. Superior limbic conjunctival biopsies were performed at the 8th and 30th day in 5 rabbits of each group. The conjunctiva was fixed with 10 percent formaldehyde, followed by HE and PAS staining. Morphohistometric quantitative analyses were performed to evaluate the following parameters: inflammatory infiltrate, epithelial thickness, number of goblet cells, diameter and number of blood vessels. RESULTS: At the 8th and 30th posttreatment days, all groups, except one that received artificial tears, exhibited a diffuse inflammatory infiltrate, composed by lymphocytes and neutrophils, which was denser in the timolol group than in the prostaglandin (PG) analogues groups. At the 30th day, the timolol group also showed an increased subepithelial collagen density and a significant increase in epithelial thickness (p=0.0035). The goblet cell density was significantly increased at the 8th day in the group treated with travoprost (p=0.0006), and at the 30th day in those treated with bimatoprost (p=0.0021) and latanoprost (p=0.009). CONCLUSIONS: Although a moderate, diffuse inflammatory infiltrate was observed in PG-treated eyes, no changes in conjunctival epithelial thickness or subconjunctival collagen density were observed with these medications, suggesting that these drugs induce fewer changes than timolol maleate in the rabbit conjunctiva.

OBJETIVOS: Comparar alterações histológicas induzidas por medicação anti-glaucomatosa na conjuntiva de coelhos. MÉTODOS: Cinqüenta coelhos da raça Nova Zelândia foram divididos em 5 grupos de 10 animais. Os olhos esquerdos foram tratados com uma gota diária de bimatoprosta 0,03 por cento, travoprosta 0,004 por cento, latanoprosta 0,005 por cento, maleato de timolol 0,5 por cento ou lágrimas artificiais contendo cloreto de benzalcônio (BAK) por 30 dias. Os olhos direitos serviram como controles. Foram realizadas biópsias conjuntivais límbicas superiores no 8º e 30º dias em 5 coelhos de cada grupo. A conjuntiva foi fixada com formaldeído 10 por cento, seguido por coloração de HE e PAS. Foi realizada análise quantitativa morfohistométrica para avaliar os seguintes parâmetros: infiltrado inflamatório, espessura epitelial, número de células caliciformes, diâmetro e número de vasos sanguíneos. RESULTADOS: No 8º e 30º dias de tratamento, todos os grupos, exceto aquele que recebeu lágrimas artificiais, exibiram infiltrado inflamatório difuso, composto por linfócitos e neutrófilos, sendo mais denso no grupo timolol do que nos grupos dos análogos de prostaglandinas. No 30º dia, o grupo timolol apresentou um aumento na densidade de colágeno subepitelial e um aumento significativo da espessura epitelial (p=0,0035). A densidade de células caliciformes aumentou significativamente no 8º dia no grupo tratado com travoprosta (p=0,0006), e no 30º dia nos grupos tratados com bimatoprosta (p=0,0021) e latanoprosta (p=0,009). CONCLUSÕES: Embora tenha sido observado um infiltrado inflamatório difuso e moderado nos olhos tratados com análogos de prostaglandinas, não houve alterações na espessura epitelial conjuntival ou densidade colágena subepitelial com essas medicações, sugerindo que essas drogas induzem menores alterações que o maleato de timolol na conjuntiva de coelhos.

Effects of topical benzalkonium chlorid on corneal epithelium

The present study was designed to investigate the long and short term topical effects of Benzalkonium chloride [BAC] on the corneal epithelium with low and high concentrations used in commercial ophthalmic preparations. Forty eight guinea pigs [ninety six eyes] of Dunkin Hartley strains were procured from NIH Islamabad, and randomly divided into four long term [A] and four short term treatment [B] groups. The analysis of the results showed significant decrease [p<0.05] in the thickness and number of epithelial cell layers. The incidence of epithelial desquamation, erosions, and ulceration was more in those experimental groups which received higher concentration of BAC more frequently than those receiving lower concentration and instilled less frequently. It is, therefore, suggested that a better and safe substitute for BAC or preservative free eye drops should be formulated to prevent the hazards of this toxic substance

Benzalkonium Chloride Induced Bronchoconstriction in Patients with Stable Bronchial Asthma

BACKGROUND: Although benzalkonium chloride (BAC)-induced bronchoconstriction occurs in patients with bronchial asthma, BAC-containing nebulizer solutions are still being used in daily practice in Korea. The aim of this study was to evaluate the effects of inhaled aqueous solutions containing BAC. METHDOS: Thirty subjects with bronchial asthma and 10 normal controls inhaled up to three 600 microgram nebulized doses of BAC using a jet nebulizer. FEV1 (forced expiratory volume at one second) was measured 15 minutes after each dose. Inhalations were repeated every 20 minutes until FEV1 decreased by 15% or more (defined as BAC-induced bronchoconstriction) or the 3 doses were administered. RESULTS: The percent fall in FEV1 in response to BAC inhalation was significantly higher in asthmatics than in normal subjects (p<0.05). BAC administration in subjects with asthma reached a plateau (maximal effect). BAC-induced bronchoconstriction was found in 6 asthmatics (20%), with two responders after the 2nd inhalation and 4 after the 3rd inhalation. The percent fall in FEV1 in response to the 1st inhalation of BAC was significantly higher in asthmatics with higher bronchial hyperresponsiveness (BHR) than in those with lower BHR. CONCLUSIONS: This study suggests that the available multi-dose nebulized solution is generally safe. However, significant bronchoconstriction can occur at a relatively low BAC dose in asthmatics with severe airway responsiveness.

Anaphylaxis Caused by Benzalkonium in a Nebulizer Solution

Benzalkonium chloride (BAC) is commonly used as a bactericidal preservative in nebulizer solutions, and can cause paradoxical onchoconstriction following nebulizing therapy in some asthmatics. We describe a case of anaphylactic shock in a 23-yr-old asthmatic woman following an intradermal skin test with a salbutamol solution containing BAC. Since she complained of cough and dyspnea after inhalation therapy with a nebulizer solution, we conducted an intradermal skin test using the same solution, which contained BAC. About 10 min later, the patient reported dizziness, palpitations, and dyspnea. On examination, tachycardia, tachypnea, and hypotension were found. She was resuscitated with a subcutaneous injection of epinephrine and an infusion of saline. One month later, we conducted a bronchial provocation test with BAC, and she showed a positive response.